1. Field of the Invention
The invention relates to a serial connection of solar cells having integrated semiconductor elements.
The invention also relates to a method for the production of a serial connection of solar cells having integrated semiconductor elements.
The invention also relates to a photovoltaic module with a serial connection of solar cells.
2. Description of Related Technology
In industry, there is an increasing demand for methods for producing serial connections of solar cells. Particularly in the special field of photovoltaics where semiconductor particles are incorporated into a layer system in order to form a p-n junction, it is practical to combine areas of thin layers and semiconductor particles to form cells or arrays and to connect these cells in series so as to be able to tap higher voltages. The problem of the serial connection of solar cells having incorporated semiconductor particles, however, has not yet been satisfactorily solved.
DE 100 52 914 A1, for instance, describes a semiconductor component system in which a semiconductor structure formed of layers with incorporated semiconductor particles is completely punctured at predefined places. Insulated conductor pins are inserted into these holes that have a size of a few hundred μm and these pins are firmly connected to a conductive layer on the front. The serial connection of the arrays is achieved by installing conductor bridges, after which the arrays are electrically separated from each other at the end of the procedure. The disconnection points are encapsulated with insulating and concurrently adhesive materials.
In another embodiment, which is also described in DE 100 52 914 A1, the approach taken during the production of the semiconductor component system is that different semiconductor component types (n-type material and p-type material) are applied alternately onto defined surface areas. Thus, areas with positive or negative electrodes are alternately formed on one side of a system, and these electrodes can be connected in series by an integrated connection. For this purpose, the electrode layers are interrupted alternately on the top and on the bottom. The placement of different semiconductor component types in order to create a surface with different electrodes, however, is an expensive method.
Moreover, U.S. Pat. No. 4,407,320 discloses a method for the production of solar cells in which spherical semiconductor elements are incorporated into an insulating layer. The spheres have a semiconductor of n-type material on one side whereas they have a semiconductor of p-type material on the other side. In each case, a conductive layer is applied onto both sides of the insulating layer in order to connect the spheres to each other. Furthermore, conductive separation lines are made consisting of spheres, a paste or, for example, a wire. In order to produce a serial connection, alternating cuts are made into the conductive layers on both sides of the conductive separation line.
It is also a known procedure to configure independent spherical semiconductor elements that constitute complete semiconductors, including the requisite electrodes. For example, EP 0 940 860 A1 describes using a spherical core to make a spherical semiconductor element by means of masking, etching steps and the application of various material layers. Such semiconductor elements can be used as solar cells if the p-n junction is selected in such a way that it can convert incident light into energy. If the p-n junction is configured in such a way that it can convert an applied voltage into light, then the semiconductor element can be employed as a light-emitting element.
Moreover, U.S. Pat. No. 5,578,503 discloses a method for the rapid production of chalcopyrite semiconductor layers on a substrate in which individual layers of the elements copper, indium or gallium and sulfur or selenium are applied onto a substrate in elemental form or as a binary interelemental compound. The substrate with the layer structure is then quickly heated up and kept at a temperature of ≧350° C. [≧662° F.] for between 10 seconds and one hour.